Akatsuki (spacecraft)

Akatsuki
A model of the spacecraft Akatsuki
NamesVenus Climate Orbiter (VCO)
PLANET-C
Mission typeVenus orbiter
OperatorJAXA
COSPAR ID2010-020D
SATCAT no.36576
WebsiteJAXA
JAXA Special Site
Mission duration13 years, 11 months
Spacecraft properties
ManufacturerNEC Space Technologies
Launch mass517.6 kg (1,141 lb)
Dry mass320 kg (710 lb)
Dimensions1.04 × 1.45 × 1.44 m (3.4 × 4.8 × 4.7 ft)
Power>700 watts at 0.7 AU
Start of mission
Launch date21 May 2010, 21:58:22 (2010-05-21UTC21:58:22Z) UTC
RocketH-IIA 202
Launch siteTanegashima YLP-1
End of mission
Declared29 May 2024
Last contactApril 2024
Orbital parameters
Reference systemCytherocentric
Eccentricity0.971
Pericytherion altitude1,000–10,000 km (620–6,210 mi)
Apocytherion altitude370,000 km (230,000 mi)
Inclination3.0°
Period10.8 days
Flyby of Venus (failed insertion)
Closest approach6 December 2010, 23:49:00 UTC
Distance550 kilometers (340 mi)
Venus orbiter
Orbital insertion7 December 2015
PLANET series

Akatsuki (あかつき, 暁; "Dawn"), also known as the Venus Climate Orbiter (VCO) and Planet-C, was a Japan Aerospace Exploration Agency (JAXA) space probe tasked with studying the atmosphere of Venus. It was launched aboard an H-IIA 202 rocket on 20 May 2010, but failed to enter orbit around Venus on 6 December 2010. After the craft orbited the Sun for five years, engineers successfully placed it into an alternative Venusian elliptic orbit on 7 December 2015 by firing its attitude control thrusters for 20 minutes and made it the first Japanese satellite orbiting Venus.

By using five different cameras working at several wavelengths, Akatsuki studied the stratification of the atmosphere, atmospheric dynamics, and cloud physics. Astronomers working on the mission reported detecting a possible gravity wave (not to be confused with gravitational waves) in Venus's atmosphere in December 2015.

JAXA lost contact with the probe in late April 2024.